A Review of Research Progress on Fractionation Characteristics and Acquisition Methods of Rare Earth Elements in Carbonate Minerals

Authigenic carbonate minerals deposited from paleo-surface water can retain the fractionation characteristics of rare earth elements in water when deposited. The environmental conditions of the water at the time affect these characteristics. Therefore, these characteristics can be used as a reliable indicator for the paleo-environmental information of deposited water.

Based on previous studies, the influence of pH, salinity, dissolved oxygen and hydrothermal input of paleo-surface water on the fractionation characteristics of rare earth elements are reviewed, and the methods of tracing the paleo-environment information and obtaining the characteristics information of rare earth elements in carbonate minerals are summarized.

At present, laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and acid dissolution-inductively coupled plasma-mass spectrometry are the mainstream analytical methods used to obtain the fractionation characteristics of rare earth elements in carbonate minerals.

It is rare to find samples that only contain carbonate minerals, so samples are usually carbonate rocks exposed on the earth's surface. However, carbonate rocks have been inevitably mixed with terrigenous minerals (such as clay, quartz, feldspar) and authigenic non-carbonate minerals during their formation, which will disturb the original rare earth elements fractionation characteristics of the carbonate minerals. Unfortunately, neither method mentioned earlier was successful in avoiding this interference.

The future study on the fractionation characteristics of rare earth elements should first explore the methods to accurately obtain the fractionation characteristics of carbonate minerals in carbonate rocks.